Is there a correlation between valence and energy?

To begin the visualisation of the selected corpus let us take a look at two variables called energy and valence. How do they differ from the 90s to the modern day rap music and is there a correlation between the two variables? Valence and energy are both variables that measure from 0.0 to 1.0. Valence is referring to the emotional quality the music conveys: 1 being very positive, happy and/or uplifting and 0.0 being angry, regretful or sad. Energy gives us an idea about the intensity and the activity of the track. A really energetic track would feel rousing for example. We can see that there is more fluctuation in the modern rap music when we look at valence and overall we see that the most popular hiphop/rap songs from both time spans all have a relatively high energy, most of them being around 0.5 or higher and that overall the “Early” graph which is representing the 90s, has more tracks with higher valence compared to the later period. It seems like there is a correlation between energy and valence in these popular hiphop/rap songs in both periods: when the valence is high, the energy also is relatively high. It’s important to mention that there are some exceptions to this though, such as “Check the Rhime” from A Tribe Called Quest released in 1991 (the blue dot in the upper left corner of the “Early” graph). You can hoover over the points in the scatter plot to see the track names, the exact release date and the exact values for the variables energy and valence; if you are familiar with 90’s hiphop or popular rap songs from recent years you will probably recognize some of the track names!

Is there a correlation between speechiness and danceability?

What is timbre and what are timbre coefficients?

This graph conveys the Spotify timbre coefficients Timbre is everything about an audio file that is separated from the sound qualities pitch, duration and volume. Timbre can be seen as a tone color or tone quality. For example, think about a violin and a piano that would both play a musical tone like C4. This tone could have the same pitch, same duration and the same volume but will differ in timbre. Timbre is the tone quality and tone color of a specific sound; it is a comprehensive concept that is sometimes difficult to put into words and can also be difficult to visualise. This graph contains the 12 timbre coefficients that Spotify uses to analyse an audio file and this is pretty ambigious to interprete. The only people who have assigned a real meaning to them are Spotify engineers, and they’ve kept information about this exact meaning of these values strictly internal. When we take a quick look, there seems to be a lot of similarity between the two, but there are also significant differences in shape and range in certain coefficients. For example at c05, c07 and c08. The first coefficient actually is based on the loudness variable; so besides the fact volume usually isn’t a factor in timbre, Spotify uses loudness as one of their timbre coefficients. Try to take a good look at c01 before going to the next page, or feel free to come back to this page after visiting the next, although small, this graph has visualized the specific values of the loudness variable of this corpus very accurately and it is fun to see how you can recognize the shape of the boxplots I will present on the next page into these shapes!

Conclusions and assumptions based on the boxplots

One of my hypotheses was that modern rap music would have higher loudness than 90s hiphop music. This boxplot shows that the modern rap music has a higher median, but that the 90’s actually has the highest max loudness value of the whole corpus! The range of loudness for 90s hip hop music (from -14.73 to -2.43) is way wider than that of modern rap music (from -9.31 to -3.37, when we leave out the outlier), this indicates that there is greater variability in loudness within 90’s hip hop music; the interquartile range from both boxplots are a good visual representation for this. Overall, the boxplots suggest that modern rap music tends to be louder than 90’s hip hop music on average; because it has a more concentrated distribution of loudness values and has a higher median whilst the IQR range is way smaller. Nevertheless it is noteworthy to mention that the third quartile of the 90’s hip hop is higher than the modern rap music and, like I mentioned earlier, the loudest track of this corpus is from the 90’s. However, the possibility of these tracks being remastered or other factors that may have affected the loudness of the music cannot be ruled out based on the boxplots alone and this could be a really decisive factor on why the 90’s boxplot has the highest max loudness value. This corpus only consists of the most popular tracks and therefore it makes sense to assume these tracks have been remastered before they where uploaded on Spotify.

Conclusions and assumptions based on the mean tempo and the standard deviation

For this graph we are using looking at the mean tempo of all the tracks of the corpus, the standard deviation is shown on the y-axis. One first observation when looking at this graph is that the standard deviation overall is very low; we can conclude that there is not a lot of variance in the calculated means of the tempi. Something we would expect with hiphop and rap music in general, and therefore also from both these periods, as the beats and rhythm usually are very repetitive and steady. It is a logical conclusion that this also explains why this type of music generally has such high danceability values, as we saw earlier. Besides this we can see a clear difference between the oldschool hiphop from the 90’s and the modern rap music. As the oldschool hiphop music (apart from the 3 outliers on the right) has significantly lower mean tempo than the modern rap music. One interesting observation, something we saw earlier in the valence and energy graph too, is that the modern rap music shows a lot of fluctuation compared to the 90’s period. We can see a steady cluster of some points around 140/150 BPM but also a lot of different values of BPM, where the oldschool really has a steady cluster off all the points, besides the 3 outliers with high BPM, from around 80 to roughly 115 BPM.

Self-Similarity Matrices for “Juicy”

Conclusion/discussion